Tax season is a stressful time for many freelancers. To help you ease the pain for next year, I chatted with Sunny Widerman of Personal Tax Advisors in Toronto about the most common tax blunders.

1. Ignoring the taxman.

When I asked Sunny to name the number one screw-up, I wasn’t expecting this: “The biggest mistake people make is not reading the letters the CRA sends.” Yes, those unmistakable pale-brown envelopes might contain bad news, but maybe not as bad as you think. “You could be in very little trouble,” says Sunny. Maybe you forgot to send in a slip, or maybe you’re a year or two behind in filing your taxes. Whatever the transgression, “the news will get immensely worse if you don’t read the letter,” says Sunny. “The government always gives lots of warning: ‘If this happens again and we don’t hear from you…’ and then it escalates. If you don’t read the letters and you don’t call them, the government feels like it has to bring out the big guns, and that can be very uncomfortable.”

2. Not setting aside tax money.

Save yourself a lot of stress by putting aside money year-round (try using a separate bank account). Sunny says that 15% of gross income is sufficient for most freelancers, though it could be higher or lower depending on your situation (how many expenses you have, whether you contribute to an RRSP, if you have kids, etc.). “If you still owe tax at the end of the year, raise the percentage for next year, and if you saved too much, lower it a bit.”

3. Keeping lousy records.

I hang on to the receipts for any work-related expense: cab rides to clients’ offices, sushi dates with other writers, seminars, Internet service, iPhone apps, etc. It takes a while to get into the habit, but it’s worth the effort—you could save a lot at tax time. Many people don’t realize what they can write off, says Sunny. “They don’t ask me until they come in, but by then they don’t have the records of what they spent. For example, screenwriters could write off part of their DVD rentals—that’s research.” Check out Sunny’s handy guide to expenses. (And once you’ve filed your taxes, don’t toss the backup materials—the government says you have to keep your financial records for seven years.)

4. Mixing up deadlines.

Self-employed people (and their spouses or common-law partners) get more time to file: The deadline is June 15. But if you owe money, you still need to pay by April 30 like everyone else, says Sunny. If you take longer, expect to be charged interest. Waiting until June 15, for example, means that about 1% will be added to your tax bill—a trade-off some freelancers are willing to accept in exchange for extra time.

5. Waiting too long to get an HST number.

Most freelancers know about the $30,000 rule: You must register to charge HST once your sales exceed $30,000 per year. What you might not realize is that “year” refers to any 12-month period, not a calendar year. “Most people sign up eventually, but the thing is, that $30,000 line? When you cross it, nobody tells you,” says Sunny. “People think, ‘Well, I didn’t register for it, and nobody’s giving me a hard time, so it must be fine’—but it’s not. The CRA will give you a hard time years from now, and freelancers must pay for any HST they were supposed to be collecting before they were registered, so it has to come out of their pocket.”

Three more reasons to sign up sooner: 1) Without an HST number, you’re essentially telling clients that you don’t earn very much; 2) When you hit the $30,000 mark, you’ll be too busy to learn about HST; and 3) You get to keep some of the tax you collect. Learn more at the CRA website.

Could not agree more on all five points. Too often, freelancer writers do not take themselves seriously as business entities, or somehow (deep down) regard themselves as "Artists" who need to be free of such pedestrian encumbrances in order to stay true to their creative natures. Big mistake. If you don't behave like a professional in all ways, and especially if you don't take yourself seriously, then don't be surprised if the grownup world doesn't take you very seriously either.

Jaclyn Law is a writer and an editor with more than 17 years’ experience. Formerly copy chief at Chatelaine and managing editor at Abilities, she has freelanced full-time since 2006. Her clients include magazines, websites, non-profits and corporations. Jaclyn is president of the Toronto Chapter of the Professional Writers Association of Canada and a member of the Editors’ Association of Canada.